title: A numerical study of the influence of ammonia addition on the auto-ignition limits of methane/air mixtures.
abstract: In this study the auto-ignition limit of ammonia/methane/air mixtures is calculated based upon a perfectly stirred reactor model with convective heat transfer. The results of four different reaction mechanisms are compared with existing experimental data at an initial temperature of 723 K with ammonia concentrations of 0-20 mol.% and methane concentrations of 2.5-10 mol.%. It is found that the calculation of the auto-ignition limit pressure at constant temperature leads to larger relative deviations between calculated and experimental results than the calculation of the auto-ignition temperature at constant pressure. In addition to the calculations, a reaction path analysis is performed to explain the observed lowering of the auto-ignition limit of methane/air mixtures by ammonia addition. It is found that this decrease is caused by the formation of NO and NO(2), which enhance the oxidation of methane at low temperatures.
authors.affiliation: Department of Mechanical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium. filip.vandenschoor@mech.kuleuven.be
authors.forename: F
authors.initials: F
authors.lastname: Van den Schoor
authors.forename: F
authors.initials: F
authors.lastname: Norman
authors.forename: L
authors.initials: L
authors.lastname: Vandebroek
authors.forename: F
authors.initials: F
authors.lastname: Verplaetsen
authors.forename: J
authors.initials: J
authors.lastname: Berghmans
mesh_terms: D000388:Air; D000641:Ammonia / Q000737:chemistry*; D053834:Explosive Agents / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D008962:Models, Theoretical; D009569:Nitric Oxide; D009585:Nitrogen Dioxide
chemical_list: D053834:Explosive Agents; D009569:Nitric Oxide; D000641:Ammonia; D008697:Methane; D009585:Nitrogen Dioxide